Roller Grill

ABSTRACT

A roller grill for heating a pre-cooked food product includes a housing structure adapted to support the roller grill; a plurality of tubes having outer surfaces adapted to transfer heat to the pre-cooked food product; a plurality of non-metallic gears, each non-metallic gear mounted on an end of a corresponding tube; a motor including a motor shaft and adapted to generate a rotational power through the motor shaft at a first rotational speed; and a drive sub-assembly adapted to transfer the rotational power from the shaft to the plurality of non-metallic gears at a second rotational speed.

TECHNICAL BACKGROUND

This disclosure relates to a roller grill or griddle for heating and/orreheating pre-cooked food product.

BACKGROUND

Various apparatus are used to heat and/or reheat prepared consumerpre-cooked food products. In some instances, cylindrically shapedpre-cooked food products, such as hotdogs, tacquitos, cheese burgerbites, and sausage links, may be prepared using a roller grillapparatus, which may include a number of heated, rotating tubes uponwhich the pre-cooked food products rest and rotate. While the heatconducting and/or radiating from the tubes and the rotation of the tubesallow the pre-cooked food products to be heated substantially uniformly,these features can also impose detrimental effects on other componentsof the roller grill apparatus. For example, heat conducted and/orradiated from the ends of the tubes is transferred to rotating drivemechanism components in contact with the ends of the tubes, such aschains, lubricants, bearings, and other components. The heat conductedand/or radiated through these components, as well as the mechanicalengagement of these components with one another during operation of theroller grill apparatus, can cause gradual deterioration and eventualfailure of such components.

Conventionally, roller grills and/or griddles used for heating and/orreheating pre-cooked food products have used chain drive assemblies todrive (e.g., rotate) tubular heating surfaces on which the pre-cookedfood products may be placed. The chain drive assemblies typicallyutilize a metallic chain that engages metallic sprockets mounted on thetubular heating surfaces. Due in part to the metal-on-metal contact, aswell as the heat energy conducted through and/or radiated from thesprockets and chain from the tubular heating surfaces (and othercomponents of conventional roller grills), the chain drive assembly mayrequire regular maintenance (e.g., lubrication, adjustment of the chainand/or the sprockets to maintain suitable engagement, and otherwise).Without such regular maintenance, conventional roller grills oftenexperience high failure rates.

In some instances, pre-cooked food products must be heated to a minimuminternal temperature in order to, for example, kill bacteria that cancause food related illness. For instance, certain standards (e.g., NSFInternational) have been established that require pre-cooked foodproduct to be heated to a minimum internal temperature for safetyreasons.

SUMMARY

In one general embodiment, a roller grill for heating a pre-cooked foodproduct includes a housing structure adapted to support the rollergrill; a plurality of tubes having outer surfaces adapted to transferheat to the pre-cooked food product; a plurality of non-metallic gears,each non-metallic gear mounted on an end of a corresponding tube; amotor including a motor shaft and adapted to generate a rotational powerthrough the motor shaft at a first rotational speed; and a drivesub-assembly adapted to transfer the rotational power from the shaft tothe plurality of non-metallic gears at a second rotational speed.

In a first aspect combinable with the general embodiment, the first andsecond rotational speeds are substantially identical.

In a second aspect combinable with any of the previous aspects, thenon-metallic gears include a heat resistive material having a continualduty max temperature rating of between about 120° F. and about 500° F.

In a third aspect combinable with any of the previous aspects, thenon-metallic gears include a heat resistive material having a continualduty max temperature rating of between about 120° F. and about 200° F.

In a fourth aspect combinable with any of the previous aspects, thedrive sub-assembly includes a timing pulley coupled to a shaft having atleast one worm gear mounted thereon and in contacting engagement with atleast one of the plurality of non-metallic gears.

In a fifth aspect combinable with any of the previous aspects, the driveassembly includes a timing belt coupled to the motor and the timingpulley and adapted to transfer the rotational power generated by themotor into rotary motion of the tubes through contacting engagement ofthe worm gear with the non-metallic gear.

In a sixth aspect combinable with any of the previous aspects, at leastone of the non-metallic gears includes a helical spur gear.

In a seventh aspect combinable with any of the previous aspects, atleast one of the worm gears includes a screw worm gear.

In an eighth aspect combinable with any of the previous aspects, thetiming belt includes a plurality of teeth protruding from a surface ofthe timing belt, the teeth engageable with a plurality of correspondingteeth disposed on a surface of the timing pulley.

In a ninth aspect combinable with any of the previous aspects, the drivesub-assembly further includes a timing gear mounted on the shaft andengageable with the timing belt.

In a tenth aspect combinable with any of the previous aspects, the drivesub-assembly further includes a plurality of idler gears mounted to aportion of the housing structure and contactingly engaged with theplurality of non-metallic gears.

In an eleventh aspect combinable with any of the previous aspects, theidler gears are adapted to transfer the rotational power from the motorto the plurality of non-metallic gears at the second rotational speed.

In a twelfth aspect combinable with any of the previous aspects, thedrive sub-assembly further includes a drive gear coupled to the shaft ofthe motor, the drive gear adapted to transfer the rotational power fromthe motor to the plurality of idler gears.

In a thirteenth aspect combinable with any of the previous aspects, thedrive sub-assembly further includes at least one transfer gear incontacting engagement with at least one of the idler gears and adaptedto transfer the rotational power from the drive gear to the least one ofthe plurality of idler gears.

In a fourteenth aspect combinable with any of the previous aspects, theplurality of non-metallic gears include a plurality of timing pulleys,each timing pulley comprising a notched circumferential surface.

In a fifteenth aspect combinable with any of the previous aspects, thedrive sub-assembly further includes a timing belt coupled to the motorand contactingly engaged with the notched circumferential surfaces ofthe timing pulleys, the timing belt adapted to transfer the rotationalpower generated by the motor to the tubes at a second rotational speed.

In a sixteenth aspect combinable with any of the previous aspects, thedrive sub-assembly further includes a plurality of idler pulleys havingsubstantially smooth circumferential surfaces, where the timing belt iscontactingly engaged with the smooth circumferential surfaces of theplurality of idler pulleys.

In a seventeenth aspect combinable with any of the previous aspects, thedrive sub-assembly includes a timing gear mounted on the shaft andengageable with the timing belt.

In an eighteenth aspect combinable with any of the previous aspects, atleast one of the non-metallic gears includes a self-lubricating gear.

Various embodiments of a roller grill according to the presentdisclosure may include one or more of the following features. Forexample, the roller grill may operate in one or more selectable heatingand/or reheating modes, such as a “Preparation” mode or a“Ready-to-Serve” mode. In some embodiments, the roller grill can includeone or more of a cover plate and a plenum plate that serve as heat sinksby absorbing heat radiating from roller grill heating tubes and/or fromdrive assembly components included within the roller grill.

Various embodiments of a roller grill according to the presentdisclosure may also include one or more of the following features. Forexample, the roller grill may include a lubricator designed to clean andlubricate a drive chain included within the roller grill, such that anappropriate amount of lubricant is provided to the drive chain duringoperation of the roller grill. Furthermore, the lubricator may be usedwith any chain-driven system that needs regular lubrication maintenance,such as a bicycle chain. In some embodiments, the roller grill may havea chain glide that causes the drive chain of the roller grill to engagemore than one tooth of sprockets (e.g., sprockets located between endsprockets) included within the roller grill. This multiple toothengagement may reduce the probability of the chain being displaced fromthe sprockets and reducing the frictional wear on the chain and on thesprockets. In some examples, the roller grill can include rollers thatincrease the engagement of the drive chain with teeth on more than onesprocket at the same time.

Various embodiments of a roller grill according to the presentdisclosure may also include one or more of the following features. Forexample, the roller grill may utilize a belt drive assembly coupled to aworm gear assembly (e.g., a screw worm gear assembly) to rotate one ormore heating tubes. In some examples, the cooling cycle can extend thelife of the timing belt and/or provide the timing belt with a longerlife as compared to a drive chain. In some examples, the cooling cyclecan drop the temperature of the timing belt by up to 50° F. In someembodiments, the cooling cycle may provide the timing belt with a lifeof up to six years. In some embodiments, the roller grill may utilize adirect drive assembly, thereby eliminating belts and chains.

These general and specific embodiments may be implemented using adevice, system or method, or any combinations of devices, systems, ormethods. The details of one or more embodiments are set forth in theaccompanying drawings and the description below. Other features,objects, and advantages will be apparent from the description anddrawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIGS. 1A-1E illustrate views of an example embodiment of a roller grillutilizing a direct drive assembly in accordance with the presentdisclosure;

FIGS. 2A-2D illustrate views of an example embodiment of a roller grillincluding a belt drive assembly including one or more worm gears inaccordance with the present embodiments;

FIGS. 3A-3B illustrate views of another example embodiment of a rollergrill utilizing a belt drive assembly in accordance with the presentdisclosure;

FIGS. 4A-4C illustrate views of another example embodiment of a rollergrill utilizing a chain drive assembly in accordance with the presentdisclosure;

FIGS. 5A-5B illustrate views of example embodiments of a roller grilltube in accordance with the present disclosure;

FIGS. 6A-6D illustrate views of example embodiments of a roller grillhaving a chain drive assembly or a belt drive assembly according to thepresent disclosure;

FIGS. 7A-7B illustrate example embodiments of a bearing block that maybe used to support a rotating shaft of a roller grill according to thepresent disclosure;

FIGS. 8A-8D illustrate an example worm gear that may be used in a rollergrill according to the present disclosure; and

FIGS. 9A-9B illustrates an example bushing plate that may be used in aroller.

DETAILED DESCRIPTION

This disclosure relates to apparatus for heating and/or reheatingprepared consumer pre-cooked food products, and more particularly, toroller grills and/or griddles used for heating and/or reheatingcylindrically shaped pre-cooked food products, such as hotdogs andsausage links. Although in some embodiments, a roller grill according tothe present disclosure may only heat and/or reheat a pre-cooked foodproduct, in other embodiments, a roller grill according to the presentdisclosure may cook a raw food product.

In a general embodiment, a roller grill includes two side housings, abottom housing, and multiple heating tubes that are disposed parallel toone another, across a volume defined between upper regions of oppositepanels of the two side housings, and above the bottom housing. Theheating tubes are positioned sufficiently close to one another, suchthat their positioning allows a pre-cooked food product tosimultaneously rest atop two adjacent heating tubes. The heating tubesare further designed to rotate 360 degrees and have outer surfaces thatare adapted to transfer heat to pre-cooked food products, therebyallowing the heating tubes to heat and/or reheat pre-cooked foodproducts that rest atop the heating tubes.

In some embodiments, the roller grill may include a belt drive assemblyhaving worm gears that provides rotary motion to the heating tubes. Forexample, the belt drive assembly can be driven by a motor that providesrotary motion to a timing belt that transfers the motion to a timingpulley, which further rotates a shaft on which worm gears are mountedand engage spur gears that are coupled to ends of the heating tubes. Insome embodiments, the belt drive assembly can have timing pulleyscoupled to the ends of the heating tubes and multiple idler pulleys thatprovide alternating heating and cooling cycles, respectively, for thetiming belt during operation of the roller grill. In some examples, thetiming pulleys can be maintained on the ends of the heating tubes byTeflon flanges.

In some embodiments, the roller grill may include a chain drive assemblyhaving sprockets that provides rotary motion to the heating tubes. Forexample, the chain drive assembly can be driven by a motor that providesrotary motion to a chain, which transfers the motion to sprocketscoupled to the ends of the heating tubes. In some embodiments, theroller grill can further include a lubricator that surrounds the chainand cleans and lubricates and cools the chain substantially constantlysuch that an appropriate amount of lubricant is provided to the chain.In some embodiments, the roller grill can include one or both of a chainglide or multiple rollers that cause the chain to simultaneously engagemore than one tooth of the sprockets, which may reduce the wear on oneor both of the chain or the sprockets.

In some embodiments, the roller grill may have a direct drive assemblyincluding a drive gear coupled to a motor and in engagement with one ormore transfer gears configured to transfer rotational motion of thedrive gear to matched sets of gears directly coupled to heating tubes.The gears may, in some embodiments, be spur gears. In some embodiments,the gears may be helical spur gears. In some embodiments, the gears maybe non-metallic, such as, for example, a high-temperature plastic. Insome embodiments, for example, one or more gears directly coupled toheating tubes may be a high-temperature plastic such as, for example,polystyrene, nylon, Teflon, polyethylene, polypropylene, polyvinylchloride and polytetrafluoroethylene (PTFE), and other plastic material)that has a continual duty max temperature rating of between about 250°F. and about 500° F. In some embodiments, for example, one or moretransfer and/or idler gears may be a high-temperature plastic that has acontinual duty max temperature rating of between about 120° F. and about200° F.

FIGS. 1A-1E illustrate views of an example embodiment of a roller grill100 utilizing a direct drive assembly for heating and/or reheatingpre-cooked food products, such as, for example, cylindrically shapedpre-cooked food products including hotdogs, sausage links, and otherproducts. With reference to FIG. 1A in particular, the roller grill 100includes two side housings 105 a and 105 b and a bottom housing 110 thatis attached to and disposed between lower regions of panels of the twoside housings 105 a and 105 b. The weight of the roller grill 100 issupported by multiple legs 115 that are mounted underneath and nearcorners of the bottom housing 110. The roller grill 100 further includesmultiple heating tubes 120 that are disposed parallel to one another,across a volume defined between upper regions of opposite panels of thetwo side housings 105 a and 105 b, and above the bottom housing 110. Theheating tubes 120 are positioned sufficiently close to one another, suchthat their positioning allows a pre-cooked food product 125 tosimultaneously rest atop two adjacent heating tubes 120. One or moreannular shaped dividers 130 may be mounted on one or more heating tubes120 in order to prevent contact between two pre-cooked food products 125resting atop common heating tubes 120 or to restrict lateral movement ofpre-cooked food products 125 resting atop the heating tubes 120.

In some embodiments, the roller grill 100 may be approximately 36″ intotal length, and the heating tubes 120 may be approximately 35.625″ inlength. In some examples, the wall thickness of a heating tube may bebetween approximately 5/64″ and approximately ⅛.″ In some examples, thewidth of the roller grill 100 may depend on the number of heating tubes120 included within the roller grill 100. In some examples, the rollergrill 100 can include multiple (e.g., 4, 8, 16, or other number) heatingtubes 120.

In some embodiments, the heating tubes 120 have outer surfaces that areadapted to transfer heat to pre-cooked food products 125 (e.g.,non-stick surfaces, cleanable surfaces, or otherwise). The heating tubes120, in some embodiments, are further designed to rotate 360 degrees,which consequently rotates the pre-cooked food products 125 360 degreesthat are in contact with the heating tubes 120. The heating tubes 120may be heated by multiple electric resistive heat elements. In someembodiments, at least one of the electric resistive heat elements may bedisposed within a bore of at least one of the heating tubes 120. In someexamples, the heat conducted to the surfaces of the heating tubes 120allows them to heat/and or reheat the pre-cooked food products 125. Insome instances, the electric resistive heat elements can enable thesurface temperatures of the heating tubes 120 to reach up to 300° F. Inany event, the heating tubes 120 can heat the pre-cooked food products125 to an internal temperature of about 160° F., or other temperature,to ensure that any bacteria is killed and/or eliminated.

As illustrated, the roller grill 100 may also include a drip plate 180extending between the side housings 105 a and 105 b and underneath theheating tubes 120. In some embodiments, the drip plate 180 may define abottom side of a volume extending from directly underneath the heatingtubes 120 to the drip plate 180 and between the side housings 105 a and105 b. Such a volume, in some embodiments, may define a sanitary volumeinto which no mechanical components of the roller grill 100 (e.g.,gears, motors, shafts, and other components) may extend. The drip plate180 may, in some embodiments, be a cleanable surface that catchesdrippings and other solids and/or liquids from the pre-cooked foodproduct 125.

In some embodiments, the roller grill 100 can include a controller (notshown) that sets the roller grill 100 to operate in one or more heatingmodes. For example, the heating modes may include a “Preparation” modethat heats pre-cooked food products 125 to a set minimum preparationtemperature (e.g., 160° F. internal) or a “Ready-to-Serve” mode thatmaintains the internal temperature of the pre-cooked food products 125at a set serving temperature by cycling the heat on and off. In someexamples, the preparation temperature of the heating tubes 120 may reachup to 300° F. In some examples, the serving temperature of the heatingtubes 120 may reach up to 240° F. in order to maintain an internalpre-cooked food product temperature in the range of 140-160° F. Theroller grill 100 can further be designed to operate in other heatingmodes (e.g., a timed heating mode, an overnight heating mode, a “wakeup” heating mode, and others).

Turning to FIGS. 1B-1E, top, end, and side views of a portion of theroller grill 100 utilizing a direct drive assembly are illustrated. Asillustrated, the roller grill 100 includes a plenums 102 a and 102 benclosed within the side housings 105 a and 105 b in which the directdrive assembly may be disposed. The direct drive assembly may drive(e.g., rotate) the heating tubes 120 to heat and/or reheat pre-cookedfood product. As illustrated, each heating tube 120 is installed over atubular portion of a heating tube gear 140, which in turn, is installedthrough apertures in the side housing 105. A bushing 135 a may also beinstalled through the aperture of the side housing 105 such that theheating tube 120 is disposed within the bushing 135 a and may move(e.g., rotate) within the bushing 135 a. In some embodiments, asillustrated in FIG. 9A, the bushing 135 a may be a paired bushing, suchthat two heating tubes 120 are inserted through a single bushing 135 a.

In the illustrated embodiment, a plenum plate 155 may be installed inthe plenum 102 a and to a surface of the side housing 105. Asillustrated, the plenum plate 155 may extend substantially an entirewidth of the plenum 102 a (as shown in FIG. 1C) and from a bottom edgeof the plenum 102 a to just above a midpoint of one or more idler gears145. In some embodiments, the idler gears 145, as well as one or moretransfer gears 160, may be mounted to the plenum plate 155. Forinstance, the gears 145 and 160 may be mounted through a mechanicalfastener disposed through an axis of the particular gear and through theplenum plate 155. In alternative embodiments, studs may be mounted(e.g., welded) on to the plenum plate 155 over which the gears 145 and160 may be mounted. In any event, the gears 145 and 160 may befree-spinning gears mounted to the plenum plate 155 without penetrationsthrough the side housing 105 (e.g., into a sanitary volume below thepre-cooked food product 125).

In the illustrated embodiment of the roller grill 100, the plenum plate155 include one or more ventilation holes 195 that allow fluid (e.g.,airflow) communication between the plenum 102 a and a volume definedbetween the bottom housing 110 and the drip plate 180 and also definedbetween the side housing 105. In some embodiments, airflow may becirculated between the plenum 102 a and an ambient airspace through, forexample, the ventilation holes 195 and one or more louvered openings inthe bottom housing 110.

In the illustrated embodiment, a retainer plate 190 a (e.g., theretainer plate 915 shown in FIG. 9A) may be mounted over the bushing 135a through attachment (e.g., mechanical) with the side housing 105. Theretainer plate 190 a may sandwich the bushing 135 a against the sidehousing 105, thereby preventing (all or partially) rotational movementof the bushing 135 a during movement (e.g., rotation) of the heatingtubes 120.

FIG. 1B illustrates heating elements 150 a (e.g., heaters with spadeterminals) to which wires may be coupled and thereby electricallycoupled to a power source. The heating elements 150 a may, in someembodiments, be an electric resistance heater installed through theheating tube 120 (e.g., all or partially) that may generate heat powerto increase a temperature of an outer surface of the heating tube 120.In some embodiments, each heating tube 120 may include an individualheating element 150 a. Alternatively, heating elements 150 a may beinstalled in every other heating tube 120 (e.g., alternating heatingtubes 120) or otherwise.

In the illustrated roller grill 100, the idler gears 145 are mountedbelow and engaged with the heating tube gears 140. Further, theillustrated roller grill 100 includes a drive gear 165 disposed on ashaft 170 of a motor 175 (shown in FIG. 1D) that may be mounted in abottom cavity of the roller grill 100 (defined by the side housings 105a and 105 b, the drip plate 180, and the bottom housing 110). The drivegear 165 contactingly engages a transfer gear 160 within a series oftransfer gears 160 to transfer rotational motion of the shaft 170 to thetransfer gears 160. Although three transfer gears 160 are illustrated inFIG. 1C, alternative embodiments may include more or fewer transfergears 160. In some embodiments, one or more of the transfer gears 160may be helical spur gears (e.g., helical gear 800).

As illustrated, one of the transfer gears 160 may be engaged with one ormore of a plurality of idler gears 145 disposed across a width of theside housing 105. As illustrated, the idler gears 145 may be spacedevenly across the plenum plate 155. The roller grill 100 also includesheating tube gears 140 that are coupled (e.g., inserted into) torespective heating tubes 120. For example, as illustrated, there may bea 1:1 ratio of heating tube gears 140 and heating tubes 120. In someembodiments, one or more of the idler gears 145 and/or heating tubegears 140 may be helical spur gears (e.g., helical gear 800).

As illustrated, a cover plate 185 a may be disposed in the plenum 102 aand mounted to a top interior surface of the side housing 105. In someembodiments, the cover plate 185 a may cover ends of the heating tubegears 140. In some embodiments, the cover plate 185 a may be mountedadjacent a gear head portion of the heating tube gear 140 such that aconcave portion extends into the gear head portion adjacent a beveledsurface (e.g., as shown in FIG. 9B). In some embodiments, electricalwiring coupled to the respective heating elements 150 a inserted throughthe heating tube 120 may be installed within a volume defined by theconcave portion, thereby saving space within the plenum 102 a.

The gears 140, 145, 160, and 165 may, in some embodiments, be spurgears. In some embodiments, the gears 140, 145, 160, and 165 may behelical spur gears. In some embodiments, the gears 140, 145, 160, and165 may be non-metallic, such as, for example, a high-temperatureplastic. In some embodiments, for example, one or more gears 140 may bea high-temperature plastic such as, for example, polystyrene, nylon,Teflon, polyethylene, polypropylene, polyvinyl chloride,polytetrafluoroethylene (PTFE), and other plastic material) that has acontinual duty max temperature rating of between about 250° F. and about500° F. In some embodiments, for example, one or more gears 145, 160,and/or 165 may be a high-temperature plastic that has a continual dutymax temperature rating of between about 120° F. and about 200° F.

In some embodiments, the gears 140, 145, 160, and 165 (and other rollersdescribed herein, such as gears 225 and 230 and pulleys 325 a, 330 a, assome examples) may be self-lubricating. For example, in some embodimentshaving non-metallic gears 140, 145, 160, and 165, a material that formsthe gears 140, 145, 160, and 165 may be impregnated with or otherwisecontain a lubricant material, such as, for example, silicon, or otherlubricant material. During operation of the roller grill 100, thelubricant material may exude from one or more of the gears 140, 145,160, and 165, thereby providing for decreased failure rates due to lackof lubricant between the gears 140, 145, 160, and 165 and othercomponents (e.g., chains, belts, or other components).

Turning to FIG. 1E, a side view of a non-drive side of the roller grill100 is illustrated. In some embodiments, only one side housing 105 a mayenclose (at least partially) one or more gears and other components ofthe direct drive assembly. In alternative embodiments, both sidehousings 105 a and 105 b may enclose (at least partially) a portion ofone or more (e.g., two) direct drive assemblies as described above. Forexample, there may be two motors 175 with each motor 175 driving (e.g.,rotating) half of a total number of heating tubes 120 via independentdirect drive assemblies. Each independent direct drive assembly may beenclosed within separate side housings 105 a and 105 b.

As illustrated, one of the plenums 102 b enclosed by the side housing105 b (shown in FIG. 1E) is substantially free of gears and other directdrive assembly components. As illustrated, the heating tube 120 mayinclude heating element 150 b extending from this end of the tube 120and may extend through the side housing 105 b and be secured to the sidehousing 105 b by a bushing 135 b (as described above). The bushing 135 bmay be sandwiched against an interior surface of the side housing 105 bby a retainer plate 190 b (as described above). In the illustratedembodiment, a cover plate 185 b is mounted to the side housing 105 b andadjacent the bushing 135 b. In some embodiments, a bearing 197 may bemounted between the bushing 135 b and the retainer plate 190 b so as to,for example, provide a bearing (e.g., wear) surface between the bushing135 b and the retainer plate 190 b.

In operation, the motor 175 of the roller grill 100 may rotate the shaft170, which in turn rotates the drive gear 165. The drive gear 165, inturn, transfers rotational movement to the transfer gears 160. One ofthe transfer gears 160 is engaged with one or more of the idler gears145 such that rotational movement is transferred from the transfer gears160 to the engaged idler gear 145. The engaged idler gear 145 is also incontacting engagement with at least one of the heating tube gears 140,and transfers rotational movement to the at least one heating tube gear140. Rotational movement is thus transferred to each of the idler gears145 and heating tube gears 140, thereby rotating the heating tubes 120.

FIGS. 2A-2D illustrate views of an example embodiment of a roller grill200 including a belt drive assembly including one or more worm gears.FIG. 2A shows that the roller grill 200 includes a side housing 205 anda bottom housing 210 that is attached to and disposed between lowerregions of plates of the side housing 205 and a corresponding sidehousing on an opposite end of the roller grill 200 (not shown).Referring now to FIG. 2B, the weight of the roller grill 200 issupported by multiple legs 215 that are mounted underneath and nearcorners of the bottom housing 210.

FIGS. 2A-2B illustrate the roller grill 200 further including multipleheating tubes 220 that are disposed parallel to one another, across avolume defined between upper regions of opposite panels of the two sidehousings 205, and above the bottom housing 210. An end of each heatingtube 220 extends through a respective hole within the panel of the sidehousing 205 into a plenum space 223 provided by the side housing 205. Insome embodiments, the width of the plenum space 223 is approximately1.625.″ Within the plenum space 223, each heating tube 220 and isengaged with a respective spur gear 225 included within the belt driveassembly. In some examples, each spur gear 225 is mounted in the end ofthe respective heating tube 220 and is maintained on the end by arespective bushing 250 and/or other components. In some examples, thespur gears 225 may be helical spur gears. Within the plenum space 223,the spur gears 225 are further engaged with worm gears 230 disposedadjacent (e.g., beneath) the spur gears 225 and mounted on a shaft 235that extends along at least a portion of the width of the roller grill200.

In some embodiments, the ratio of spur gears 225 to worm gears 230 is1:1. In some embodiments, the ratio of spur gears 225 to worm gears 230is 2:1 or another ratio. In some embodiments, a spur gear 225 may be ahelical spur gear. In some embodiments, a worm gear 230 may be a screwworm gear. In some embodiments, the shaft 235 may be coupled to the sidehousing 205 by one or more bearing blocks 260.

FIG. 2C illustrates that the shaft 235 is further coupled to a timingpulley 240 having multiple teeth disposed on a cylindrical surface thatengage multiple teeth protruding from a surface of a timing belt 245.The timing belt 245 sequentially engages multiple components of the beltdrive assembly that may be fully or partially disposed within the bottomhousing 210 of the roller grill 200. For example, such componentsinclude, as illustrated, a first pulley 255, a timing gear 270 havingmultiple teeth disposed on a circumferential surface and mounted on ashaft of a motor 265, and a second pulley 275 disposed vertically higherthan the first pulley 255. In some examples, one or both of the pulleys255 or 275 can be a timing pulley (i.e., with a grooved circumferentialsurface). In some examples, one or both of the pulleys 255 or 275 mayhave substantially smooth outer cylindrical surfaces.

During operation of the roller grill 200, the motor 265 generates rotarymotion of the heating tubes 220 by using the timing belt 245 to transferrotary motion to the worm gears 230 engaged with the spur gears 225.Power generated by the motor 265 drives rotation of the timing gear 270mounted on the shaft of the motor 265, which, by engagement of the teethdisposed on the surface of the timing gear 270 with the teeth protrudingfrom the surface of the timing belt 245, drives rotation of the timingbelt 245. Thus, in the illustrated embodiment, the timing belt 245extends from the bottom housing 210 through the panel of the sidehousing 205 and into the plenum space 223 provided by the side housing205 to engage the timing pulley 240. Alternatively, the motor 265 may bemounted elsewhere in or on the roller grill 200 (e.g., in the plenumspace 223 or otherwise).

Engagement of the teeth protruding from the surface of the timing belt245 with teeth disposed on the surface of the timing pulley 240 drivesrotation of the timing pulley 240, which in turn rotates the shaft 235.Rotary motion of the shaft 235 drives rotation of the worm gears 230,which consequently drives rotation of the spur gears 225 due to theirengagement with the worm gears 230, and further drives rotation of theheating tubes 220 that are coupled to the spur gears 225.

In some embodiments, one motor 265 may be coupled to two belt driveassemblies located at opposing sides of the roller grill 200. In someembodiments, a first motor 265 may be coupled to a first belt driveassembly located at a first side of the roller grill 200, while a secondmotor 265 may be coupled to a second belt drive assembly located at asecond side of the roller grill 200. In other embodiments, there may betwo (or more) belt drive assemblies, with each assembly driving a subsetof a total number of heating tubes 220 of the roller grill 200. Eachbelt drive assembly may drive the corresponding subset of heating tubes220 from the same end of the roller grill 200 or from opposed ends.

Referring now to FIG. 2D, in some embodiments, a cover plate 280 may beattached to the side housing 205, such that the cover plate 280 isadjacent to the spur gears 225 and the worm gears 230. The cover plate280 is disposed to cover various components of the drive assembly (i.e.,spur gears 225, worm gears 230, and other components) and is visiblewhen the side housing 205 is displaced from the roller grill 200. Thecover plate 280 may further serve as a heat sink that absorbs heatradiated from the heating tubes 220 and/or the drive assemblycomponents, thereby transferring heat away from the drive assemblycomponents and transferring heat to, for example, the plenum space 223provided the side housing 205 or an ambient space exterior to the rollergrill 200.

FIGS. 3A-3B illustrate views of another example embodiment of a rollergrill 300 utilizing a belt drive assembly. The roller grill 300 includesa side housing 305 and a bottom housing 370 that is attached to anddisposed between lower regions of panels of the side housing 305 and acorresponding side housing on an opposite end of the roller grill 300(not shown). The weight of the roller grill 300 is supported by multiplelegs 310 that are mounted underneath and near ends of the bottom housing370. The roller grill 300 further includes multiple heating tubes 355that are disposed parallel to one another, across a defined volumebetween upper regions of opposite panels of the two side housings 305,and above the bottom housing 370. The heating tubes 355 are furtherpositioned sufficiently close to one another so as to allow a pre-cookedfood product 365 to simultaneously rest atop two adjacent heating tubes355. One or more annular shaped dividers 360 may be mounted on eachheating tube 355 in order to prevent contact between two pre-cooked foodproducts 365 positioned along common heating tubes 355 or to restrictlateral movement of a pre-cooked food product 365 resting atop theheating tubes 355.

In some embodiments, an end of each heating tube 355 extends through arespective hole within the panel of the side housing 305 into a plenumspace 357 provided by the side housing 305, where the heating tubes 355are coupled to one or more belt drive assemblies. In this example, theroller grill 300 includes two belt drive assemblies, a first belt driveassembly 301 a and a second belt drive assembly 301 b. In alternativeembodiments, however, the roller grill 300 may include only one beltdrive assembly or multiple (e.g., two or more) belt drive assemblies.The first belt drive assembly 301 a includes, as illustrated, a timingbelt 315 a, multiple timing pulleys 325 a, multiple upper idler pulleys330 a, two lower idler pulleys 340 a, a tensioning pulley 335 a, and atiming gear 345 a. However, in alternative embodiments, the first beltdrive assembly 301 a may include more or fewer of these listedcomponents. The second belt drive assembly 301 b includes, asillustrated, a timing belt 315 b, multiple timing pulleys 325 b,multiple upper idler pulleys 330 b, two lower idler pulleys 340 b, atensioning pulley 335 b, and a timing gear 345 b. However, inalternative embodiments, the second belt drive assembly 301 b mayinclude more or fewer of these listed components.

In the illustrated embodiment, the timing belts 315 a and 315 b includeteeth protruding from a circumferential surface that are adapted toengage teeth disposed on a surface of one or more corresponding timingpulleys 325 a, 325 b. The timing belts 315 a and 315 b are secured onthe one or more corresponding timing pulleys 325 a and 325 b by one ormore bushings 320 a and 320 b. Alternatively, one or both of the timingbelts 315 a and 315 b may be smooth belts, with no teeth or otherprotrusions on a circumferential surface.

In some embodiments, the teeth protruding from a first surface of thetiming belt 315 a, 315 b engage the teeth disposed on the surface of oneor more timing pulleys 325 a, 325 b alternate with a second surface ofthe timing belt 315 a, 315 b engaging one or more upper idler pulleys330 a, 330 b. Following engagement of the timing belt 315 a, 315 b withthe one or more timing pulleys 325 a, 325 b and the one or more upperidler pulleys 330 a, 330 b, the teeth protruding from the surface of thetiming belt 315 a, 315 b engage teeth disposed on a surface of atensioning pulley 335 a, 335 b, which may be mounted on a verticallyadjustable, spring-loaded bracket assembly 343 a, 343 b. The bracketassembly 343 a, 343 b allows the tensioning pulley 335 a, 335 b to beadjusted vertically, thereby further allowing adjustment of tension inthe timing belt 315 a, 315 b. In some embodiments, the roller grill 300may not include the tensioning pulley 335 a, 335 b and the bracketassembly 343 a, 343 b.

In some embodiments, the belt drive assemblies 301 a and 301 b caninclude one or more lower idler pulleys 340 a, 340 b. Followingengagement of the teeth protruding from the surface of the timing belt315 a, 315 b with the teeth disposed on the surface of the tensioningpulley 335 a, 335 b, the teeth protruding from the surface of the timingbelt 315 a, 315 b engage teeth disposed on the surface of the timinggear 345 a, 345 b. The timing gear 345 a, 345 b may be coupled to amotor (not shown) located in the bottom housing 370 of the roller grill300 that drives rotary motion of the timing belt 315 a, 315 b.

In some embodiments, one or more of the upper idler pulleys 330 a, 330 bmay be coupled to a plenum plate 350, which can serve as a heat sinkthat transfers heat away from the timing belt 315 a, 315 b and timingpulleys 325 a, 325 b.

In some embodiments, a louver 375 may be disposed along the bottomsurface of the bottom housing 370, allowing cool air to pass into thebottom housing 370 and cool the motor and any other drive componentsdisposed within the bottom housing.

Referring now to FIG. 3B, in some embodiments, a plenum plate 380 may beattached to each side housing 305. Various components of the driveassembly, such as, for example, the timing gears 345 a and 345 b, theidler pulleys 340 a and 340 b, and other components, may be mounted on(e.g., via mechanical fasteners) on the plenum plate 380. The plenumplate 380 may further serve as a heat transfer surface that absorbs heatradiated from the heating tubes 355 and the drive assembly components,thereby transferring heat away from the drive assembly components. Insome embodiments, the plenum plate 380 may include one or moreventilation holes 395 allowing fluid (e.g., airflow) communicationbetween the plenum 357 and a volume defined underneath the heating tubes355 and within the bottom housing 210. Such airflow may also becommunicated through the louvers 375. The roller grill 300 may alsoinclude multiple bushings 390 that are respectively mounted over theends of the multiple heating tubes 355 and that, for example, preventthe timing pulleys 325 a, 325 b from moving inward on the multipleheating tubes 355. Further, the bushings 390, which may be similar to,for instance, the bushing 900 shown in FIG. 9A, may provide a bearingsurface for the heating tubes 355 to rotate within during operation ofthe roller grill 300. In some examples, the plenum plate 380 may have athermal conductivity that is greater than or equal to 200 Btu/(hr·ft·F)at a temperature of 250° F.

During operation of the roller grill 300, one or more motors (locatedwithin the bottom housing 370, not shown in FIGS. 3A-3B) drive rotationof the heating tubes 355 via the belt drive assemblies 301 a, 301 b. Insome embodiments, a single motor may drive both belt drive assemblies301 a, 301 b. In other embodiments, each belt drive assembly 301 a, 301b (and other belt drive assemblies), may each be driven by a dedicatedmotor.

Power generated by the motor drives rotation of the timing gear 345 a,345 b mounted on a shaft (not shown in FIGS. 3A-3B) of the motor, which,by engagement of the teeth protruding from the surface of the timingbelt 315 a, 315 b with teeth disposed on the surface of the timing gear345 a, 345 b, drives rotary motion of the timing belt 315 a, 315 b.Engagement of teeth protruding from the surface of the timing belt 315a, 315 b with teeth disposed on the surface of the timing pulleys 325 a,325 b further provides rotary motion to the timing pulleys 325 a, 325 b,which consequently rotate the heating tubes 355. Engagement of the teethprotruding from the timing belt 315 a, 315 b with teeth and surface ofthe timing belt 315 a, 315 b disposed on the surface of the idlerpulleys 330 a, 330 b, 340 a, 340 b and the tensioning pulley 335 a, 335b, further rotates the idler pulleys 330 a, 330 b, 340 a, 340 b and thetensioning pulley 335 a, 335 b, respectively.

In some embodiments, the arrangement of the timing pulleys 325 a, 325 band one or more of the idler pulleys 330 a, 330 b, 340 a, 340 b, thetensioning pulley 335 a, 335 b, and the timing gear 345 a, 345 b createsa series of alternating timing belt heating cycles and timing beltcooling cycles, respectively. In some embodiments, the timing beltheating cycles are provided by heat radiated from the timing pulleys 325a, 325 b. When heat is generated within the heating tubes 355 by, forexample, electric resistive heating elements, the heat is transferred tovarious components of the roller grill assembly 300, including thebushings 390 and the timing pulleys 325 a, 325 b. As the timing belt 315a, 315 b engages with the timing pulleys 325 a, 325 b, the timing belt315 a, 315 b absorbs heat from the timing pulleys 325 a, 325 b (i.e.,the timing pulleys 325 a, 325 b transfer heat to the timing belt 315 a,315 b).

In some embodiments, the timing belt 315 a, 315 b may be made from lowheat conducting material. For example, the timing belt 315 a, 315 b maybe insulated from the transfer of heat from, for instance, the heatingtubes 355 through the timing pulleys 325 a, 325 b.

In some embodiments, the timing belt cooling cycles are provided by heatabsorbed by one or more of the idler pulleys 330 a, 330 b, 340 a, 340 b,the tensioning pulley 335 a, 335 b, and the timing gear 345 a, 345 b.For example, as the timing belt 315 a, 315 b engages with the idlerpulleys 330 a, 330 b, 340 a, 340 b, the idler pulleys 330 a, 330 b, 340a, 340 b absorb heat from the timing belt 315 a, 315 b (i.e., the idlerpulleys 330 a, 330 b, 340 a, 340 b transfer heat away from the timingbelt 315 a, 315 b). In some embodiments, the roller grill 300 may notinclude the lower idler pulleys 340 a, 340 b or the tensioning pulley335 a, 335 b. Thus, in some embodiments, the presence of one or more ofthe idler pulleys 330 a, 330 b, 340 a, 340 b and the tensioning pulley335 a, 335 b may determine the length and total cooling effect of thecooling cycle.

In some examples, the thermal conductivity of the timing pulleys 325 a,325 b is less than that of one or more of the idler pulleys 330 a, 330b, 340 a, 340 b, the tensioning pulley 335 a, 335 b, and the timing gear345 a, 345 b. For example, in some embodiments, the thermal conductivityof the timing pulleys 325 a, 325 b may be less than or equal to 17Btu/(hr·ft·F) at a temperature of 250° F., while the thermalconductivity of one or more of the idler pulleys 330 a, 330 b, 340 a,340 b, the tensioning pulley 335 a, 335 b, and the timing gear 345 a,345 b may be greater than or equal to 200 Btu/(hr·ft·F) at a temperatureof 250° F. In some instances, the cooling cycle can drop the temperatureof the timing belt 315 a, 315 b by up to 50° F. In some examples, thealternating heating cycles and cooling cycles may extend the life of thetiming belt 315 a, 315 b. For example, the cooling cycle may provide thetiming belt 315 a, 315 b with a life of up to six years, whereas a drivechain, in contrast, may need to be changed once per year.

In some embodiments, the timing pulleys 325 a, 325 b may be a low heatconductive material, such as plastic. In some embodiments, the idlerpulleys 330 a, 330 b may be a high heat conductive material, such asaluminum. In some embodiments, the idler pulleys 340 a, 340 b may be alow heat conductive material, such as plastic. In some embodiments, thetiming gear 345 a, 345 b may be a high heat conductive material, such asaluminum.

FIGS. 4A-4C illustrate views of another example embodiment of a rollergrill 400 utilizing a chain drive assembly. The roller grill 400includes two side housings 405 (one shown in FIG. 4A), and the weight ofthe roller grill 400 is supported by multiple legs 410 that are mountedunderneath and near corners of a bottom housing. The roller grill 400also includes multiple heating tubes and multiple sprockets 420 that arerespectively coupled to ends of the multiple heating tubes. In someembodiments, a chain 415 provides rotary motion to the heating tubes byengaging the sprockets 420. The chain 415 is driven by one or moremotors within a bottom housing of the roller grill 400 (not shown inFIGS. 4A-4B) as the chain 415 engages a drive gear 430 coupled to themotor. In this example, the roller grill 400 includes one chain driveassembly; however, in alternative embodiments, the roller grill 400 mayinclude more than one chain drive assembly.

In some embodiments, one motor may be coupled to two chain driveassemblies located at opposing sides of the roller grill 400. In someembodiments, a first motor may be coupled to a first chain driveassembly located at a first side of the roller grill 400, while a secondmotor may be coupled to a second chain drive assembly located at asecond side of the roller grill 400.

In some embodiments, a lubricator 425 may be attached to the sidehousing 405 and disposed around the chain 415 as the chain 415 travelsthrough the drive assembly. In some examples, the lubricator 425 may beunattached to the side housing 405 and mounted on the chain 415. In thisexample, the lubricator 425 can have pins 450 disposed adjacent externalsurfaces of the lubricator 425 (e.g., protruding from the housing 405)that prevent the lubricator 425 from moving past a fixed distance fromthe drive sprocket 430. The lubricator 425, therefore, may befree-floating on the chain 415 (e.g., unattached to the side housing405) and substantially prevented from moving with movement of the chain415 towards the drive sprocket 430.

In some embodiments, the lubricator 425 may be approximately 4″ long inlength. The lubricator 425 includes two lubricant blocks 435, a shellcover plate 440, and a clam shell cover plate 445. Each lubricant block435 has two grooves cut into a surface of the lubricant block 435, thesurface of each lubricant block 435 disposed adjacent to and facing themirrored surface of the other lubricant block 435. In some examples,when the surfaces of the two lubricant blocks 435 are disposed adjacentto and facing each other, the opening created by the grooves allows theplates 455 and rollers 460 of the chain 415 to travel through thelubricator 425 with engaging contact with the lubricant blocks 435.

Each lubricant block 435 is further impregnated with lubricant. In someembodiments, the lubricator 425 cleans and lubricates the chain 415substantially constantly such that an appropriate amount of lubricant isprovided to the chain 415, while excess lubricant on the chain 415 isremoved. For example, the lubricator 425 can replace lubricant that mayhave evaporated from the chain 415 over time due to heat transferred tothe chain 415, and/or the lubricator 425 can remove lubricant that mayhave congealed on the chain 415 over time. As the chain 415 enters thelubricant blocks 435 during operation of the roller grill 400, excesslubricant on the chain 415 is scraped away (e.g., by external edges ofthe lubricant blocks 435, the “I”-shaped recess defined between thelubricant blocks 435, or other edge surface). As the chain 415 continuesto pass through and in contact with the facing surfaces of the lubricantblocks 435, lubricant impregnated in the lubricant blocks 435 isdisposed on the chain 415. The clam shell cover plate 440, in someembodiments, can serve as a spring that urges the two lubricant blocks435 together to maintain their contact. Further, the shell cover plate440 may maintain the lubricant blocks 435 disposed around the chain 415as the chain 415 travels through the lubricator 425.

In some embodiments, the lubricator 425 can be used with anychain-driven system that needs regular lubrication maintenance tofunction properly. For example, the lubricator 425 may be used on abicycle chain, a motorcycle chain, a food heating assembly chain, orotherwise. Further, although the lubricant blocks 435 are illustrated asseparate portions, in some embodiments, the lubricator 425 may have asingle lubricant block with one or more of the illustrated channelsand/or grooves formed therethrough.

FIG. 4C illustrates a sectional view of the lubricator 425. Asillustrated, the lubricant blocks 435 are urged together by the shellcover plate 440 to form an interface at matching surfaces of the blocks435. Upon interface of the lubricant blocks 435, grooves 470 a and 470 bdefine a channel 472. In some embodiments, the channel 472 may extend anentire length of the blocks 435 with openings at each end surface of thelubricant blocks 435. As illustrated, a portion of the chain 415, suchas, for example, a plate 455 of the chain 415, may fit within thechannel 472. In some embodiments, the channel 472 may be sized so as tocontactingly engage the portion of the chain 415 (e.g., the plates 455)as the chain 415 is moved through the lubricator 425. In such a fashion,lubricant impregnated into the lubricant blocks 435 may be transferredto the chain 415.

As illustrated, upon interface of the lubricant blocks 435, grooves 475a and 475 b define another channel 477. In some embodiments, the channel477 may extend the entire length of the blocks 435 with openings at eachend surface of the lubricant blocks 435. As with the channel 472, thechannel 477 may be sized so as to contactingly engage the portion of thechain 415 (e.g., the plates 455) as the chain 415 is moved through thelubricator 425. In such a fashion, lubricant impregnated into thelubricant blocks 435 may be transferred to the chain 415 in cooperationwith the channel 477.

As illustrated, ridges 480 a and 480 b may be formed in the lubricantblocks 435 in between the grooves 470 a and 475 a, and grooves 470 b and475 b, respectively. The ridges 480 a and 480 b may be sized to allow aportion of the chain 415 (e.g., the rollers 460) to move through anotherchannel 482 formed between the lubricant blocks 435. As illustrated, thechannel 482 may be open to the channels 472 and 477, thereby defining asubstantially “T” shaped opening through the lubricant blocks 435. Insome embodiments, lubricant from the lubricant blocks 435 may betransferred to the rollers 460 as the chain 415 is moved through thelubricant blocks 435 through, for instance, contacting engagements withthe ridges 480 a and 480 b.

In some embodiments, lubricant on the chain 415 may be removed by thelubricant blocks 435 as the chain 415 enters into and/or moves throughthe lubricant blocks 435. For instance, edges on distal surfaces of thelubricant blocks 435 that define openings into the channels 472 and 477may remove excess and/or used lubricant from the chain 415 as the chain415 is moved over, and in contact with, such edges. In some embodiments,excess and/or used lubricant may also be removed from the chain 415 asthe portions of the chain 415 (e.g., the plates 455 and rollers 460)contactingly engage the lubricant blocks 435 at the grooves 470 a, 470b, 475 a, and 475 b, and at the ridges 480 a and 480 b.

FIGS. 5A-5B illustrate views of example embodiments of a roller grilltube assembly 500, 550 that may be used with a roller grill, such as oneor more of roller grills 100, 200, 300 and/or 400. Referring now to FIG.5A, in some embodiments, a roller grill tube assembly 500 includes aheating tube 505, a sprocket 510 coupled to an end of the heating tube505, and a bushing 515. In some embodiments, the sprocket 510 isinstalled over the heating tube 505 (e.g., press fit over the tube 505).In some embodiments, the bushing 515 may be a bearing inserted into thesprocket 510 that acts as a thrust bearing that prevents (all orpartially) metal-to-metal contact between the sprocket 510 and othermetal components of a roller grill.

In some examples, the sprocket 510 may allow the roller grill tubeassembly 500 to operate with a roller grill utilizing a chain driveassembly, such as the roller grill 400. During operation of a rollergrill, the bushing 515 provides a surface to transfer heat away from theheating tube 505 and the sprocket 510, thereby reducing the wear of thesprocket 510 and a chain (e.g., the chain 415) engaged with the sprocket510. In some embodiments, the bushing 515 can include a notch 520 thatengages with a ridge of the heating tube 505 or a ridge of the sprocket510 to prevent or reduce slippage of the bushing 515. In some examples,the bushing 515 is a Teflon bushing.

Referring now to FIG. 5B, in some embodiments, a roller grill assembly550 may include a heating tube 555, a pulley flange 560 coupled to anend of the heating tube 555, a timing pulley 565 coupled to the end ofthe heating tube 555, and a bushing 570. The bushing 570 may, in someembodiments, extend past the timing pulley 565 to contact a retainerplate (not shown), such as, for instance, the cover plate 280. In someembodiments, the bushing 570 may be Teflon or another bearing material.In some embodiments, the timing pulley 565 may allow the roller grilltube assembly 550 to operate with a roller grill utilizing a belt driveassembly, such as the roller grill 300. In some examples, the pulleyflange 560 may prevent the timing pulley 565 from sliding inward on theheating tube 555. In some examples, the pulley flange 560 is made ofplastic (e.g., Teflon) or steel (e.g., stainless or carbon).

FIGS. 6A-6D illustrate views of example embodiments of a roller grill600 having a chain drive assembly or a roller grill 600 having a beltdrive assembly. As shown in FIG. 6A, the illustrated roller grill 600includes a side housing 605, multiple heating tubes 610, and multiplesprockets 615 that are respectively coupled to ends of the multipleheating tubes 610. In some embodiments, as illustrated, a bearing (suchas the bushing 515) may be press-fit into each heating tube 610 andprovide a wear surface with a retainer plate (not shown) so as toprevent metal-to-metal contact with the sprockets 615 and, for instance,a retainer plate.

The roller grill 600 further includes a chain glide 620 having multipleglide recesses 625. In some embodiments, the chain glide 620 can be madeof a bearing material, such as plastic, bronze, or other wearablematerial. In some embodiments, the chain glide 620 can have a serpentineshape that causes the chain 630 to engage more than one tooth of thesprockets 615. For example, the chain glide 620 may cause the chain 630to engage with two or three teeth of the sprockets 615, rather than asingle tooth in the absence of the chain glide 620.

Engagement of the chain 630 with more than one tooth of the sprockets615 reduces the probability of the chain 630 being displaced from thesprockets 615. In some examples, engagement of the chain 630 with morethan one tooth of the sprockets 615 reduces the frictional wear on anygiven point of the chain 630 and on any given tooth of the sprockets 615by distributing forces between the chain 630 and the sprockets 615across multiple teeth of the sprockets 615. In some embodiments, each ofthe glide recesses 625 may have side skirts that maintain the positionof the chain 630 on the sprockets 615. In some examples, this canprevent damage of one or more of the chain 630, of the sprockets 615, orof other components of the chain drive assembly.

During operation of the roller grill 600, the chain 630 provides rotarymotion to the heating tubes 610 by engaging the sprockets 615 that arecoupled to the ends of the heating tubes 610. The chain 630 is driven byone or more motors within a bottom housing of the roller grill 600 (notshown in FIGS. 6A-6B) as the chain 630 engages a drive gear a coupled tothe one or more motors. As the chain 630 engages the sprockets 615, thechain 630 is contacted and further guided towards the sprockets 615 bythe chain glide 620, which causes the chain 630 to engage multiple teethof the sprockets 615. While the chain 630 is engaged with the teeth ofthe sprockets 615, the glide recesses 625 can prevent the chain 630 fromslipping off of the sprockets 615.

Referring now to FIG. 6B, in some embodiments, the roller grill 600 caninclude one or more rollers 635 coupled to the side housing 605 anddisposed above and in contact with the chain 630 and between thesprockets 615. The one or more rollers 635 can cause the chain 630 toengage more than one tooth of the sprockets 615. In some embodiments,the position of the one or more rollers 635 can increase the engagementof the chain 630 with the teeth on two separate sprockets 615simultaneously. In some examples, a roller 635 can be positioned aboveand in contact with the chain 630 and between every two sprockets 615.In some embodiments, the chain 630 may be longer than a conventionalchain for a roller grill due to increased contact between the chain 630and the teeth of the sprockets 615.

During operation of the roller grill 600, the chain 630 provides rotarymotion to the heating tubes 610 by engaging the sprockets 615 that arecoupled to the ends of the heating tubes 610. The chain 630 is driven byone or more motors within a bottom housing of the roller grill 600 (notshown in FIGS. 6A-6B) as the chain 630 engages a drive gear a coupled tothe one or more motors. As the chain 630 engages the sprockets 615, thechain 630 is contacted and further guided towards the sprockets 615 bythe rollers 635, which cause the chain 630 to simultaneously engagemultiple teeth of adjacent sprockets 615. While the chain 630 is engagedwith the teeth of the sprockets 615, the rollers 635 can also help inpreventing the chain 630 from slipping off of the sprockets 615.

Turning to FIG. 6C, another embodiment of the roller grill 600 is shownbut with a belt-drive assembly that uses a timing belt 650 engaged withgears 660 to drive (e.g., rotate) one or more heating tubes 610. Thisembodiment of the roller grill 600 further includes a belt glide 622having multiple glide recesses 627. In some embodiments, the belt glide620 can be made of a bearing material, such as plastic, bronze, or otherwearable material. In some embodiments, the belt glide 622 can have aserpentine shape that causes the belt 650 to engage more than one toothof the gears 660. For example, the belt glide 622 may cause the belt 650to engage with two or three teeth of the gears 660, rather than a singletooth in the absence of the belt glide 622.

Engagement of the belt 650 with more than one tooth of the gears 660reduces the probability of the belt 650 being displaced from the gears660. In some examples, engagement of the belt 650 with more than onetooth of the gears 660 reduces the frictional wear on any given point ofthe belt 650 and on any given tooth of the gears 660 by distributingforces between the belt 650 and the gears 660 across multiple teeth ofthe gears 660. In some embodiments, each of the glide recesses 627 mayhave side skirts that maintain the position of the belt 650 on the gears660. In some examples, this can prevent damage of one or more of thebelt 650, of the gears 660, or of other components of the belt driveassembly.

During operation of this embodiments of the roller grill 600 shown inFIG. 6C, the belt 650 provides rotary motion to the heating tubes 610 byengaging the gears 660 that are coupled to the ends of the heating tubes610. The belt 650 is driven by one or more motors within a bottomhousing of the roller grill 600 (not shown in FIG. 6C) as the belt 650engages a drive gear coupled to the one or more motors. As the belt 650engages the gears 660, the belt 650 is contacted and further guidedtowards the gears 660 by the belt glide 622, which causes the belt 650to engage multiple teeth of each of the gears 660. While the belt 650 isengaged with the teeth of the gears 660, the glide recesses 627 canprevent the belt 650 from slipping off of the gears 660.

Turning to FIG. 6D, another embodiment of the roller grill 600 is shownbut with a belt-drive assembly that uses a timing belt 650 engaged withgears 660 to drive (e.g., rotate) one or more heating tubes 610. Thisembodiment of the roller grill 600 can include one or more rollers 637coupled to the side housing 605 and disposed above and in contact withthe belt 650 and between the sprockets 615. The one or more rollers 637can cause the belt 650 to engage more than one tooth of the gears 660.In some embodiments, the position of the one or more rollers 637 canincrease the engagement of the belt 650 with the teeth on two separategears 660 simultaneously. In some examples, a roller 637 can bepositioned above and in contact with the belt 650 and between every twogears 660. In some embodiments, the belt 650 may be longer than aconventional belt for a roller grill due to increased contact betweenthe belt 650 and the teeth of the gears 660.

During operation of the roller grill 600, the belt 650 provides rotarymotion to the heating tubes 610 by engaging the gears 660 that arecoupled to the ends of the heating tubes 610. The belt 650 is driven byone or more motors within a bottom housing of the roller grill 600 (notshown in FIG. 6D) as the belt 650 engages a drive gear coupled to theone or more motors. As the belt 650 engages the gears 660, the belt 650is contacted and further guided towards the gears 660 by the rollers637, which cause the belt 650 to simultaneously engage multiple teeth ofadjacent gears 660. While the belt 650 is engaged with the teeth of thegears 660, the rollers 637 can also help in preventing the belt 650 fromslipping off of the gears 660.

FIGS. 7A-7B illustrate example embodiments of a bearing block that maybe used to support a rotating shaft of a roller grill, such as, forexample, the roller grill 200 illustrated in FIGS. 2A-2D. For instance,in some embodiments, one or more of the illustrated bearing blocks 700and/or 750 may be used to support (e.g., rotatingly) the shaft 235 onwhich the worm gears 230 are disposed. For example, in some embodiments,a bearing block 700 or a bearing block 750 may be mounted on the rollergrill 200 at or near the illustrated locations of the illustratedbearing blocks 260 and may take the place of the bearing blocks 260. Forinstance, in some embodiments, there may be four bearing blocks 700and/or 750 mounted and arranged to receive a bearing attached to theshaft 235 therethrough. Alternatively, there may be more or fewerbearing blocks 700 and/or 750 arranged on the roller grill 200 toreceive the shaft 235 therethrough.

Turning to FIG. 7A, the illustrated bearing block 700 includes avertical block 715 inserted through a yoke 705 and coupled thereto. Insome embodiments, the vertical block 715 may be directly coupled to theyoke 705, such as, for example, by welding, adhesive, or othertechnique. A shaft with an attached bearing, such as the shaft 235, maybe inserted through a bore 720 of the vertical block 715 and besupported (e.g., rotatingly) by a bearing (e.g., a roller bearing orother type of bearing) statically mounted within the bore 720 of thevertical block 715. Thus, in some embodiments, the shaft 235 may rotatewith reduced friction in the bearing block 700. In some embodiments, thevertical block 715 may comprise a press fit bearing for the shaft 235made of, for instance, stainless steel, cold rolled steel, or otherappropriate material.

The yoke 705, as illustrated, includes two winged extensions 713, witheach extension 713 having a mount hole 710 therethrough. In someembodiments, the yoke 705 may be directly coupled to the side housing205 through mechanical fasteners (e.g., sheet metal screws or otherwise)inserted through the mount holes 710. In alternative embodiments, theyoke 705 may be directly coupled to a plenum plate, such as the plenumplate 350, through mechanical fasteners (e.g., sheet metal screws orotherwise) inserted through the mount holes 710.

As illustrated, the vertical block 715 includes a mounting ledge 730. Insome embodiments, the mounting ledge 730 may interface with a portion ofthe roller grill 200, such as, for example, a plate on which the wormgears 230 may be mounted. In some embodiments, for example, the mountingledge 730 may provide for an increased alignment of the bearing block700 when mounted to the roller grill 200.

The illustrated bearing block 700 also includes a threaded bore 725. Insome embodiments, a retainer or cover plate (such as the retainer plate930 illustrated in FIG. 9B) may be attached to the bearing block 700 bya mechanical fastener threaded into the bore 725 and through a tab 940of the retainer plate. This may, in some embodiments, provide or helpprovide for the bearing block 700 to be held substantially stationaryduring operation of the roller grill. For instance, the bearing block700 may be held substantially stationary so that it does not rotate whenthe shaft 235 rotates and also is not urged laterally in parallel to thelongitudinal axis of the shaft 235 due to thrust forces exerted byrotation of the worm gears 230.

Turning to FIG. 7B, the illustrated bearing block 750 includes a bearingring 770 coupled to a yoke 755. In some embodiments, for example, thebearing ring 770 may be integral with the yoke 755, with each componentmanufactured of a metal or plastic, such as noryl (PPO) plastic (30%glass filled). A shaft, such as the shaft 235, may be inserted through abore 775 of the bearing ring 770 and be supported (e.g., rotatingly) bya bearing (e.g., a roller bearing or other type of bearing) staticallymounted within the bore 775 of the bearing ring 770. Thus, in someembodiments, the shaft 235 may rotate with reduced friction in thebearing block 750. In some embodiments, the bearing ring 770 maycomprise a press fit bearing for the shaft 235 and may include a torquesurface 780, as illustrated. In some embodiments, the torque surface 780may prevent (all or partially) rotation of the bearing in the bore 775during rotation of the shaft 235 within the bearing, as well aslongitudinal movement of the bearing under a thrust force applied by theworm gears 230.

The yoke 755, as illustrated, includes two winged extensions 760, witheach extension 760 having a mount slot 765 therethrough. In someembodiments, the yoke 755 may be directly coupled to the side housing205 through mechanical fasteners (e.g., sheet metal screws or otherwise)inserted through the mount slots 765. In alternative embodiments, theyoke 755 may be directly coupled to a plenum plate, such as the plenumplate 350, through mechanical fasteners (e.g., sheet metal screws orotherwise) inserted through the mount slots 765.

As illustrated, the bearing ring 770 includes a mounting ledge 790. Insome embodiments, the mounting ledge 790 may interface with a portion ofthe roller grill 200, such as, for example, a plate on which the wormgears 230 may be mounted. In some embodiments, for example, the mountingledge 790 may provide for an increased alignment of the bearing block750 when mounted to the roller grill 200 (e.g., a plenum plate).

The illustrated bearing block 750 also includes a threaded bore 785. Insome embodiments, a retainer or cover plate (such as the retainer plate930 illustrated in FIG. 9B) may be attached to the bearing block 750 bya mechanical fastener threaded into the bore 785 and through a tab 940of the retainer plate. This may, in some embodiments, provide or helpprovide for the bearing block 750 to be held substantially stationaryduring operation of the roller grill. For instance, the bearing block750 may be held substantially stationary so that it does not rotate whenthe shaft 235 rotates and also is not urged laterally in parallel to thelongitudinal axis of the shaft 235 due to thrust forces exerted byrotation of the worm gears 230.

FIGS. 8A-8D illustrate an example helical gear 800 that may be used in aroller grill, such as, for example, the roller grill 200 illustrated inFIGS. 2A-2D. In some embodiments of the roller grill 200, for instance,the helical gear 800 may be coupled to a heating tube 220 (or otherheating tube) and used to drive (e.g., rotate) the heating tube 220. Forexample, the helical gear 800 may be driven by the spur gear 225 andmounted on the shaft 235.

As illustrated, the helical gear 800 includes an outer diameter surface810 coupled to (e.g., attached to or integral with) a gear head 805having multiple teeth 815 disposed around an outer surface of the gearhead 805. A bore 820 extends through the gear head 805 and outerdiameter surface 810 and shares a centerline with the gear head 805 andthe outer diameter surface 810. As illustrated, the teeth 815 may beangled to form a helical gear (e.g., at about a 5° angle offset). Insome embodiments, there may be 21 teeth 815, with each tooth 815 havinga pitch diameter of about 1.2 inches, an outside diameter of about 1.3inches, a root diameter of about 1.08 inches, and a tooth thickness atthe pitch diameter of about 0.1 inches. Further, in some embodiments,the diameter of the bore 820 is about 0.75 inches.

As illustrated in FIG. 8D, an end of the helical gear 800 that may becoupled to a heating tube includes a beveled surface 825 around acircumference of the outer diameter surface 810. In some embodiments,the beveled surface 825 may be set-off at an angle of about 30° from aninterior surface of the outer diameter surface 810. Alternatively, otherangular offsets are possible. In some embodiments, the beveled surface825 may allow a heating element to be more easily inserted through thehelical gear 800 from the heating tube 220.

As further illustrated in FIG. 8D, the gear head 805 also includes abeveled surface 830 around a circumference of the gear head 805. In someembodiments, the beveled surface 830 may be set-off at an angle of about45° from an interior surface of the gear head 805. Alternatively, otherangular offsets are possible. In some embodiments, a retainer or coverplate (such as the retainer plate 930) may include a concave portion 935that protrudes into the gear head 805 adjacent the beveled surface 830.Thus, there may be more space allowed for wiring coupled to a heatingelement passing through the heating tube 220.

In some embodiments, the helical gear 800 may be coupled to the heatingtube 220 (or another heating tube) as follows. First the outer diametersurface 810 may be inserted (e.g., all or partially) into the heatingtube 220 until an end of the heating tube 220 is at or adjacent the gearhead 805. Next, the heating tube 220 may be punched into the outerdiameter surface 810 (e.g., by compressing the heating tube 220 into theouter diameter surface 810 and/or inserting a davit (not shown) throughthe heating tube 220 and outer diameter surface 810). Next, the assemblyincluding the helical gear 800 and heating tube 220 may be rotated, forexample, about 180°. The heating tube 220 may be punched again into theouter diameter surface 810 (e.g., by installing the heating tube 220over the outer diameter surface 810) at a location about 180° about fromthe first punch location. In such a manner, the helical gear 800 may becoupled to the heating tube 220.

FIGS. 9A-9B illustrate an example bushing 900 that may be used in aroller grill, such as, for example, one or more of the roller grills100, 200, 300, 400, and/or 600. In some embodiments, for example, thebushing 900 may be used as a bearing surface through which a heatingtube (such as, for instance, the heating tube 120) may be inserted. Asillustrated, the bushing 900 includes a pair of tubulars 910 connectedby a web 905. Although FIG. 9A shows two tubulars 910, more or fewertubulars 910 may be connected by the web 905. In some embodiments, thebushing 900 may be installed against an end plate of a roller grill,such as the side housing 205, such that the web 905 is mounted adjacentan outboard surface of the side housing 205 (e.g., facing a side plenumspace of the roller grill) and the tubular portions 910 are insertedthrough holes in the side housing 205.

As illustrated in FIG. 9A, a retainer plate 915 may also be mounted in aroller grill substantially adjacent the bushing 900. The retainer plate915 may include a number of apertures 925 receiving the tubulars 910.For instance, in some embodiments, the retainer plate 915 may be asingle piece that extends (all or partially) a width of the roller grillwith a 1:1 ratio of apertures 925 to heating tubes. In some embodiments,the retainer plate 915 may prevent (all or partially) the bushing 900from movement (e.g., rotational) during rotation of heating tubes in theroller grill.

Turning to FIG. 9B, an example embodiment of the bushing 900 isillustrated with the roller grill 200. Alternatively, the bushing 900may be used in the roller grill 100 illustrated in FIG. 1. Asillustrated, the bushing 900 may be inserted through the side housing205 such that the web 905 is in contacting engagement with an outboardsurface of the side housing 205. The retainer plate 915 may be insertedover the tubulars 910 that extend into the plenum space adjacent theoutbound surface of the side housing 205, thereby sandwiching the web905 against the side housing 205. In some embodiments, the retainerplate 915 may be attached (e.g., mechanically) to the side housing 205.

As further illustrated in FIG. 9B, the retainer plate 930 may be mountedadjacent the gear head 805 of the helical gear 800 such that the concaveportion 935 extends into the gear head 805 adjacent the beveled surface830. In some embodiments, electrical wiring coupled to a heating element(not shown) inserted through the heating tube 220 may be installedwithin a volume defined by the concave portion 935, thereby saving spacewithin the plenum 223.

A number of embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made. For example, variouscombinations of the components described herein may be provided forembodiments of similar apparatus. For instance, although belts andchains are shown in the illustrated embodiments, other types of loopedsurfaces (e.g., continuous looped surfaces) may be used in place ofbelts or chains. Accordingly, other embodiments are within the scope ofthe present disclosure.

What is claimed is:
 1. A roller grill for heating a pre-cooked foodproduct, comprising: a housing structure adapted to support the rollergrill; a plurality of tubes having outer surfaces adapted to transferheat to the pre-cooked food product; a plurality of non-metallic gears,each non-metallic gear mounted on an end of a corresponding tube; amotor comprising a motor shaft and adapted to generate a rotationalpower through the motor shaft at a first rotational speed; and a drivesub-assembly adapted to transfer the rotational power from the shaft tothe plurality of non-metallic gears at a second rotational speed.
 2. Theroller grill of claim 1, wherein the first and second rotational speedsare substantially identical.
 3. The roller grill of claim 1, wherein thenon-metallic gears comprise a heat resistive material having a continualduty max temperature rating of between about 120° F. and about 500° F.4. The roller grill of claim 1, wherein the non-metallic gears comprisea heat resistive material having a continual duty max temperature ratingof between about 120° F. and about 200° F.
 5. The roller grill of claim1, wherein the drive sub-assembly comprises: a timing pulley coupled toa shaft having at least one worm gear mounted thereon and in contactingengagement with at least one of the plurality of non-metallic gears; anda timing belt coupled to the motor and the timing pulley and adapted totransfer the rotational power generated by the motor into rotary motionof the tubes through contacting engagement of the worm gear with thenon-metallic gear.
 6. The roller grill of claim 5, wherein at least oneof the non-metallic gears comprises a helical spur gear, and at leastone of the worm gears comprises a screw worm gear.
 7. The roller grillof claim 5, wherein the timing belt comprises a plurality of teethprotruding from a surface of the timing belt, the teeth engageable witha plurality of corresponding teeth disposed on a surface of the timingpulley.
 8. The roller grill of claim 5, wherein the drive sub-assemblyfurther comprises a timing gear mounted on the shaft and engageable withthe timing belt.
 9. The roller grill of claim 1, wherein the drivesub-assembly comprises: a plurality of idler gears mounted to a portionof the housing structure and contactingly engaged with the plurality ofnon-metallic gears, the idler gears adapted to transfer the rotationalpower from the motor to the plurality of non-metallic gears at thesecond rotational speed.
 10. The roller grill of claim 9, wherein thedrive sub-assembly further comprises a drive gear coupled to the shaftof the motor, the drive gear adapted to transfer the rotational powerfrom the motor to the plurality of idler gears.
 11. The roller grill ofclaim 10, wherein the drive sub-assembly further comprises at least onetransfer gear in contacting engagement with at least one of the idlergears and adapted to transfer the rotational power from the drive gearto the least one of the plurality of idler gears.
 12. The roller grillof claim 1, wherein the plurality of non-metallic gears comprise aplurality of timing pulleys, each timing pulley comprising a notchedcircumferential surface, and the drive sub-assembly comprises: a timingbelt coupled to the motor and contactingly engaged with the notchedcircumferential surfaces of the timing pulleys, the timing belt adaptedto transfer the rotational power generated by the motor to the tubes ata second rotational speed.
 13. The roller grill of claim 12, wherein thedrive sub-assembly further comprises a plurality of idler pulleyscomprising substantially smooth circumferential surfaces, wherein thetiming belt is contactingly engaged with the smooth circumferentialsurfaces of the plurality of idler pulleys.
 14. The roller grill ofclaim 13, wherein the drive sub-assembly comprises a timing gear mountedon the shaft and engageable with the timing belt.
 15. The roller grillof claim 1, wherein at least one of the non-metallic gears comprises aself-lubricating gear.
 16. An apparatus for heating a pre-cooked foodproduct, comprising: a bottom housing mounted between a first sidehousing and a second side housing; a plurality of legs mounted to thebottom housing; a plurality of tubes having outer surfaces adapted totransfer heat to the pre-cooked food product; a plurality ofnon-metallic gears, each non-metallic gear mounted on an end of acorresponding tube; a motor comprising a motor shaft and adapted togenerate a rotational power through the motor shaft at a firstrotational speed; and a drive sub-assembly adapted to transfer therotational power from the shaft to the plurality of non-metallic gearsat a second rotational speed.
 17. The apparatus of claim 1, wherein thefirst and second rotational speeds are substantially identical.
 18. Theapparatus of claim 1, wherein the non-metallic gears comprise a heatresistive material having a continual duty max temperature rating ofbetween about 120° F. and about 500° F.
 19. The apparatus of claim 1,wherein the non-metallic gears comprise a heat resistive material havinga continual duty max temperature rating of between about 120° F. andabout 200° F.
 20. The apparatus of claim 1, wherein the drivesub-assembly comprises: a timing pulley coupled to a shaft having atleast one worm gear mounted thereon and in contacting engagement with atleast one of the plurality of non-metallic gears; and a timing beltcoupled to the motor and the timing pulley and adapted to transfer therotational power generated by the motor into rotary motion of the tubesthrough contacting engagement of the worm gear with the non-metallicgear.
 21. The apparatus of claim 5, wherein at least one of thenon-metallic gears comprises a helical spur gear, and at least one ofthe worm gears comprises a screw worm gear.
 22. The apparatus of claim5, wherein the timing belt comprises a plurality of teeth protrudingfrom a surface of the timing belt, the teeth engageable with a pluralityof corresponding teeth disposed on a surface of the timing pulley. 23.The apparatus of claim 5, wherein the drive sub-assembly furthercomprises a timing gear mounted on the shaft and engageable with thetiming belt.
 24. The apparatus of claim 1, wherein the drivesub-assembly comprises: a plurality of idler gears mounted to a portionof the housing structure and contactingly engaged with the plurality ofnon-metallic gears, the idler gears adapted to transfer the rotationalpower from the motor to the plurality of non-metallic gears at thesecond rotational speed.
 25. The apparatus of claim 9, wherein the drivesub-assembly further comprises a drive gear coupled to the shaft of themotor, the drive gear adapted to transfer the rotational power from themotor to the plurality of idler gears.
 26. The apparatus of claim 10,wherein the drive sub-assembly further comprises at least one transfergear in contacting engagement with at least one of the idler gears andadapted to transfer the rotational power from the drive gear to theleast one of the plurality of idler gears.
 27. The apparatus of claim 1,wherein the plurality of non-metallic gears comprise a plurality oftiming pulleys, each timing pulley comprising a notched circumferentialsurface, and the drive sub-assembly comprises: a timing belt coupled tothe motor and contactingly engaged with the notched circumferentialsurfaces of the timing pulleys, the timing belt adapted to transfer therotational power generated by the motor to the tubes at a secondrotational speed.
 28. The apparatus of claim 12, wherein the drivesub-assembly further comprises a plurality of idler pulleys comprisingsubstantially smooth circumferential surfaces, wherein the timing beltis contactingly engaged with the smooth circumferential surfaces of theplurality of idler pulleys.
 29. The apparatus of claim 13, wherein thedrive sub-assembly comprises a timing gear mounted on the shaft andengageable with the timing belt.